There's a new pub in town, and you can read it up.  It's a generic guide to mulch use.

Mulches for Landscapes

Mulches are materials that are applied to the soil surface, but not tilled, mixed, or combined with underlying soil. Landscape mulches are typically plant residues (organic mulches) or rock, sand, and stone (inorganic mulches). You may know that immediately after application mulches prevent weeds from germinating and reduce evaporative loss from soil surfaces, but there are other benefits as well.  And down sides, as well. 

Includes a table of common mulch materials with their benefits and potential problems.

This free publication is available by download.

Read more.  Know more.  And there's a lot more to read at ANR Publications.